Rotary switch



P. MEIER ROTARY SWITCH Dec. 30, 1969 3 Sheets-Sheet 1 Filed April 13, 1967 Pefer Meier I N VEN TOR.

' t g B958 Attorney Dec. 30, 1969 P. MEIER 3,487,179

ROTARY SWITCH Filed April 13, 1967 3 Sheets-Sheet 2 x A h Pefer Meier I N VEN TOR.

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Attorney QUA g'gRpss P. MEIER ROTARY SWITCH Dec. 30, 1969 3 Sheets-Sheet 5 Filed April 15. 1967 Fig.1O

Pe'rer Meier INVENTOR.

0w 9'- Attorney United States Patent US. Cl. 200-11 6 Claims ABSTRACT OF THE DISCLOSURE Rotary switch with an annular array of bank contacts on a support plate and a contactor in the form of a spinning top with an inclined axis whose body comprises at least one disk having a metallic frustoconical peripheral surface which upon rotation of the contactor about the center of the array in which its point is journaled in a recess of the support plate, successively sweeps the several bank contacts with a rolling motion to establish connections among them and/or between each bank contact and a central contact engaged by the point; when the disk surface is resiliently deformable, adjoining bank contacts can be spanned by it. A surrounding switch housing may entrain the contactor upon being rotated relatively to the support plate.

My present invention relates to a rotary switch to be used as a manual or automatic selector switch, stepping switch or the like.

Conventional switches of this type comprise wiper arms which, in rotating about an axis, sweep across an annular array of bank contacts; since, to minimize the voltage drop therebetween, the wiper must be held under considerable pressure against a bank contact engaged thereby, the sweep motion is generally performed against a rather high frictional resistance and leads to rapid wear of the contact surfaces.

The general object of my invention is to provide a rotary switch of this character in which friction and wear are reduced without diminution of contact pressure.

A more particular object is the provision of a rotary switch which, owing to its compact overall construction, can be readily miniaturized.

A rotary switch embodying my invention comprises primarily, an insulating plate carrying an annular array of bank contacts and, juxtaposed therewith, a contactor mounted for rotation about the center of the array, the body of the contactor resembling a spinning top and having a frustoconical conductive peripheral surface centered on an axis which includes an acute angle with the support plate. The support plate is tangent to the peripheral surface of the contactor, by virtue of the fact that the aforementioned acute angle equals half the vertex angle of the frustocone, the contactor being held under pressure against the support plate for low-resistance engagement of its peripheral surface either with a single bank contact or, particularly if its body is resiliently deformable, with a pair of neighboring bank contacts bridged thereby; if desired, a point of the contactor body may also engage a central contact to be connected in circuit with the bank contact or contacts so engaged. It is also possible to provide several concentric arrays of bank contacts coacting with respective frustoconical zones of the contactor body which, in that case, may comprise a plurality of axially spaced disks on a common stem. In each of these cases, as the contactor is rotated, its peripheral surface rolls on the support plate and on the bank contacts carried thereby.

The bank contacts, whose shape and relative position is dictated by the type of connections to be established, may be foils of highly conductive metal (e.g. silver or 3,487,179 Patented Dec. 30, 1969 gold) pasted onto the support plate or otherwise secured thereto; they could also be produced by selective etching of a conductive layer plated, sprayed or otherwise applied to an insulating substrate. The same is true, naturally, of a central contact in permanent engagement with the point of the contactor body.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1a is a side-elevational view, partly in section, of the principal elements of a rotary switch embodying the invention;

FIG. 1b is a top view of one half of a support plate forming part of the switch of FIG. 1a;

FIGS. 2a and 2b are views respectively similar to FIGS. la and 1b, illustrating a different embodiment;

FIGS. 3a and 3b are further views similar to FIGS. 1a and lb, respectively, showing still another modification;

FIG. 4 is a side view, in axial section, of still another contactor adapted to be used in a switch according to the invention;

FIG. 5 is yet another view similar to FIG. 1a, illustrating a further modification;

FIG. 6 is a sectional elevational view of a complete switch incorporating an assembly of the type shown in FIGS. 1a and 1b;

FIG. 6a is an elevational view of a miniature switch, drawn approximately to scale, embodying the construction of FIG. 6;

FIG. 7 is a top view of the switch of FIG. 6 taken partly in section on the line VIIVII thereof;

FIG. 8 is a bottom view of the same switch;

FIG. 9 is a sectional elevational view, similar to FIG. 6, of another complete switch according to the invention;

FIG. 10 is a side-elevational View, partly in section, of an electromagnetic actuator included in the switch of FIG. 10;

FIG. 11 is a top view of the actuator of FIG. 10 with its armature removed;

FIG. 12 is a top view of the support plate of the switch of FIG. 9; and

FIG. 13 is a cross-sectional view taken on the line XIIIXIII of FIG. 9.

The assembly shown in FIGS. 1a and 1b comprises a contactor 110, in the form of a spinning top with inclined axis 0, resting on an insulating support plate 114 which carries a central conductive foil 16 and an annular array of bank contacts 117 (here twelve) of which only six, designated A G, have been illustrated. Foil 16 has a depression 15 which defines the center of the array 117 and forms a seat for the bottom end 13' of an axially extending stem 13 of contactor 10 whose body, here assumed to be wholly metallic, also includes a transverse disk 11 with a frustoconical peripheral surface 11 rolling on plate 114. Thus, the angle 0: included between the plate surface and the axis 0 equals half the vertex angle of the frustocone F defined by surface 11'.

Stem 13 has an upward extension 12, beyond disk 11, which terminates in a tapering tip 12' whose projection onto the surface of plate 114 lies substantially midway between the center of rotation, 15, and a circle C bisecting the annular zone of rolling engagement between contactor and segments 117. Thus, the distance x =x is substantially half the distance D between tip 12' and a midzone of the surface 11'. If a downward force K is continuously exerted upon tip 12', the reaction forces at fulcrum 15 and at the engaged bank contact 117 will be substan tially alike and equal to K/2 to insure good contact between the conductive body 110 and the formations 16, 117 on plate 114. This force K, exerted for example in a manner described hereinafter with reference to FIGS. 6-13, may be resilient in character; alternatively, or additionally, the contactor 110 may be somewhat elastic. This contactor, in its various operating positions, bridges any of the contact combinations MA, MB etc. to close respective external circuits (not shown) in which they are connected.

The modified switch assembly shown in FIGS. 2a and 2b comprises a supporting plate 214, generally similar to plate 114, and a contactor 210 with a conductive stem 23 having a shoulder 22 against which a conductive disk 20 is held by a collar 21 press-fitted, soldered or otherwise secured onto the upwardly projecting part of the stem. Disk 20 is in the form of a corrugated membrane which allows for resilient deformation of the frustoconical periphery 22'. By virtue of this deformation, surface 22' may bridge adjoining bank contacts on plate 214. In the particular embodiment illustrated, these bank contacts are extensions 217', 217" of two conductive rings H and I, the segments 217', and 217" being unsymmetrically interleaved so as to be separated by a relatively narrow gap on one side and a relatively wide gap on the other side of each segment. If the elastic deformability of disk 20 is insufficient to allow for a bridging of the wider gap, clockwise rotation of contactor 210 (as viewed in FIG. 2b) will successively complete the following connections: open circuit (o.c.) MI MIH MH o.c. etc. With reverse rotation, the connections will be o.c. MH MHI MI o.c. etc. If the central contact M is omitted, the contactor on rotating in either direction will produce a series of spaced pulses in the circuit (not shown) connected across rings H and I.

In FIGS. 3a and 3b I have illustrated a support plate 314 with an array of bank contacts 317 (designated Q, R, S, T, U, V, etc.) and, concentric therewith, an annular contact P. A modified contactor 310, having a stem 32 with a shoulder 33, further includes two resilient metal disks 30 and 31, each similar to disk 20 (FIG. 2a) and consisting, for example, of Phosphorus bronze. The peripheries 30' and 31' of these disks lie on a common imaginary frustoconical surface, having its vertex'at the bottom end 32' of the stem, and roll on bank contacts 317 and contact ring P, respectively. Stem 32, which in this case may consist of insulating material, is tightly surrounded by a pair of collars 34, 35 holding the disks 30' and 31 against the shoulder 33. A conductive ring 36 electrically interconnects the two disks.

In the particular embodiment illustrated in FIG. 3b, the segments 317 peripherally overlap so that adjoining bank contacts are bridged by the rotating contactor 310 for a somewhat longer period than would be possible merely by virtue of the deformability of disk periphery 30 Disk 30 could, in fact, be rigid as long as disk 31 is elastic, the deformability of at least one of these disks being desirable to insure good simultaneous contact with the conductive elements on plate 314. With clockwise rotation (as viewed in FIG. 3b), the connections successively completed will be PQ PQR PR PRS etc.

In FIG. 4 I have shown a contactor 410 with a body 40 of nonconductive (e.g. plastic) material forming a stem 42 and a disk 43 generally similar to the contactor 110 of FIG. 1a; the plastic material may, however, impart a somewhat greater resiliency to the periphery 43 of disk 43. This periphery, as well as the point 42' of the stem, is coated by a metallic layer 41 so that the contactor 410 may co-operate with a set of contacts as shown in FIGS. 1b and 2b. An advantage of this arrangement is that it eliminates the need for specially insulating, in a high-voltage system, the tip 42" of the contactor stem upon which a downward pressure is exerted, as described in connection with FIG. 1a, and to which a driving force may also be externally applied, e.g. as described hereinafter with reference to FIG. 6.

In FIG. I have illustrated a modified contactor 510 whose stem 52 terminates at its frustoconical disk 51 while being lodged by a spherical head 53 in a metallic insert of plate 514 defining a central som N. At an intermediate location of stem 52 there is formed a generally spherical boss 54 designed to receive the contact pressure K, the location of this boss being so chosen that substantially equal reaction forces K/2 are again developed at central contact N and at a bank contact engaged by the periphery of disk 51. Owing to this redistribution of forces, the angle or included between the contactor axis 0 and the surface of plate 514 is considerably smaller than in the embodiments heretofore described.

Stem 52 may be somewhat resilient so that the force K may be exerted by a more or less rigid driving element 50 which rotates about an axis Z, passing through fulcrum 53, to entrain the contactor 510. Member 50, indicated only diagrammatically, may be in positive engagement with boss 54, e.g. by means of a complementary formation 55, and may be rotated either manually or automatically, e.g. by a stepping magnet as shown in FIGS. 9-12 and 13.

In FIGS. 6-8 I have illustrated a complete switch having means for rotating a contactor 610 with rolling motion about the center of a support plate 61 provided with a central contact 62 and an array of bank contacts 60. Contactor 610, here similar to contactor 110 of FIG. 1a, is also representative of any of the spinning-top configurations shown in FIGS. 2a, 3a and 4. The peripheral disk surface 63 of the contactor conductively engages the bank contacts 60 while the lower end 65 of its stem 65 is cradled in a depression of central contact 62. Each of the bank contacts 60 has an external connection in the form of a respective pin 64 traversing the plate 61, these pins forming an orthogonal array as best seen in FIG. 8. A similar pin 64 is conductively and mechanically connected to the base plate of contact 62.

A cylindrical switch housing 77 surrounds a generally cup-shaped actuator 65 of insulating material formed with an oblique bottom recess 66; a depression 67 of recess 66 grips the converging tip of 65" stem 65 under the resilient pressure member 65 intensified with the aid of an oblique slot 68 cut into the actuator. Another slot 73 across the reduced top of member 65, which is fitted into an aperture 72 of housing 77, is engageable by a screwdriver, a coin or a similar edged tool for manual rotation of member 65 within housing 77. With twelve bank contacts 60 on plate 61, the interior of housing 77 has twelve recesses 76 coacting with a ball check 71, loaded by a spring 70 in a bore 69 of actuator 65, for indexing the actuator in any of twelve operating positions which are identified by numbers on the upper surface of housing 77 as seen in FIG. 7. A mark 74 at one of the ends of slot 73 coacts with the numeral inscriptions to identify the position of the actuator and, with it, of the contactor 610.

FIG. 6a shows the switch 75 in approximately its natural size. Thus, the switch may have a diameter of about 14 mm., a height (without pins 64, 64) of about 10 mm. and a pin spacing r (FIG. 8) of 2.5 mm.

Reference will now be made to FIGS. 9l3 which show a modified actuator for electromagnetically stepping a contactor 910 representative of any of the contactors heretofore described in connection with FIGS. 1a, 2a, 3a and 4. The switch shown in its entirety in FIG. 9 comprises a support plate with bank contacts 91 (FIG. 12) which co-operate with the frustoconical periphery of contactor disk 94.

Bank contacts 91 are independently connected to pins 92 passing downwardly through plate 90 and through the insulating bottom 93 (e.g. of glass) of a surrounding switch housing 104. A further pin 92" connects with a central contact 91' forming a fulcrum for the rotary body 910; two additional pins 92 are part of the energizing leads of an electromagnetic coil 95. This coil is mounted on a nonconductive carrier 96 having a depending skirt 96 which is formed with a peripheral groove 96" receiving the support plate 90.

Carrier 96 has a bore 98 transversed by a pin 100 which is integral with a ratchet 99 and bears under pressure of a leaf spring 106 on the stem of contactor 910 whose tip is in positive engagement with a depression on the underside of the ratchet. Any rotation of element 99, 100 is thereby communicated to the contactor whose disk 94 rolls on the array of bank contacts 91. The leaf spring 106 depends by a pair of legs 107 from the under side of an insulating liner 105 at the top of housing 104 and bears with one end 106' upon pin 100; the other extremity 106" of the spring acts upon a bell-crank lever 102 which is swingably linked with the upper ends 101' of a pair of laminated iron cores 101 passing through the generally elliptical coil 95 on opposite sides of pin 100. The lower end of the nearly vertical leg of bell-crank lever 102 carries a leaf spring 103 having extremities 103, 103" which act as pawls co-operating with the teeth of ratchet 99 as best seen in FIG. 13. Member 102, which is of ferromagnetic material, forms a swingable armature which is attracted against the lower ends of cores 101, thus swinging clockwise as viewed in FIGS. 9 and 10 whenever the coil 95 is energized.

Upon such inward swing, spring leg 103' advances a ratchet tooth 99' by 18 while the opposite spring leg 103" drops behind another ratchet tooth 99". Upon the subsequent return swing due to the pressure of spring extremity 106 on the substantially horizontal leg of armature 102, tooth 99" is retracted by the spring 103 to make the ratchet 99 rotate through another 18. It will thus be seen that each energization of coil 95 advances the contactor 910, in two successive steps, from one segment 91 to the next, the first of these steps establishing a bridging position between two neighboring segments. Naturally, the number of bank contacts 91 and, therefore, of ratchet teeth 99', 99" may be varied as required.

The switch housing 104 may be filled with an inert gas, e.g. nitrogen, and should in that case be hermetically sealed.

Modifications of the specific embodiments described and illustrated, including the combination or substitution of compatible features shown in different figures of the drawing, are deemed to fall within the spirit and scope of my invention as defined in the appended claims.

I claim:

1. A rotary switch comprising:

an insulating support plate with a central depression;

an annular array of bank contacts on said support plate centered on said depression;

a contractor mounted on said support plate for rotation about said depression, said contactor having a generally disk-shaped body with a frustoconical conductive peripheral surface centered on an axis and with a stem in line with said axis projecting from said body on opposite sides, thereby forming a first extremity with a point rotatably cradled on said plate in said depression and a second extremity with a tip overlying an annular region of said supporting plate disposed substantially midway between said depression and said array upon said peripheral surface resting on said supporting plate in conductive engagement with at least one of said bank contacts;

and control means for rotating said body about said depression with said peripheral surface rolling along said array for successive engagement with said bank contacts, said control means bearing upon said tip with a pressure normal to said plate divided into substantially equal components at said point and at the area of contact between said body and said supporting plate whereby said peripheral surface is urged against the contact engaged by it.

2. A switch as defined in claim 1 wherein said support plate is provided with a central contact in the region of said depression, said point being conductively connected with said peripheral surface.

3. A switch as defined in claim 1 wherein said body has a resiliently deformable flange forming said peripheral surface, said flange being maintained by said control means under sufiicient pressure to span adjacent bank contacts in certain positions of said contactor.

4. A switch as defined in claim 1, further comprising annular contact means on said support plate concentric with said array, said body forming two disks on said stem with aligned frustoconical peripheral surfaces and in respective engagement with said array and said annular contact means, said frustoconical surfaces being conductively interconnected.

5. A switch as defined in claim 1 wherein said control means comprises a member in positive engagement with said tip and mounted for progressive rotation about an axis which passes through said depression at right angles to said plate.

6. A switch as defined in claim 5 wherein said member comprises a generally cylindrical housing provided with a recess confronting said plate and receiving said contractor, said tip being lodged in an end wall of said recess at a point offset from the axis of rotation of said housing.

References Cited UNITED STATES PATENTS ROBERT K. SCHAEFER, Primary Examiner ROBERT A. VANDERHYE, Assistant Examiner 

